Handover method and system in relay network, relay node, control base station and base station

ABSTRACT

Embodiments of the present invention provide a handover method and system in a relay network, a relay node, a control base station and a base station. The method includes: receiving, by a relay node, a first area identifier that identifies the relay node; sending a system information broadcast message carrying the first area identifier to a terminal in a coverage area; receiving a handover request message forwarded by a control base station; and performing, according to the handover request message, a control operation of accessing the relay node on the terminal. The first area identifier that identifies the relay node is allocated to the relay node, so that the terminal in the relay network can be normally handed over from the base station to the relay node.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/535,924, filed on Jun. 28, 2012, which is a continuation ofInternational Application No. PCT/CN2010/079979, filed on Dec. 20, 2010,which claims priority to Chinese Patent Application No. 200910258944.8,filed on Dec. 31, 2009, both of which are hereby incorporated byreference in their entireties.

FIELD OF THE INVENTION

The embodiments of the present invention relate to the field of mobilecommunications technologies, and in particular, to a handover method andsystem in a relay network, a relay node, a control base station and abase station.

BACKGROUND OF THE INVENTION

In a mobile communication network, a mobility management entity(Mobility Management Entity; MME) is used to perform operations such assaving mobility management context and user authentication on a terminal(User Equipment; UE) in a coverage area of a base station (E-UTRAN NodeB; eNB). The eNB and the MME are connected through an S1 interface, andthe eNBs are connected through an X2 interface. When the UE moves from acoverage area of one eNB to a coverage area of another eNB, the UE needsto be handed over from the first eNB to the second eNB.

In a conventional network, an eNB and a UE are connected through awireless network, that is, a single-hop network. However, in a relaynetwork, one or more relay nodes (Relay Node; RN) are added between aneNB and a UE, and are responsible for forwarding a radio signal sent bythe eNB one time or multiple times to the UE. Taking a simple two-hoprelay as an example, one eNB-UE radio link is divided into two radiolinks, namely, eNB-RN and RN-UE, thereby having the opportunity toreplace one poor-quality link with two good-quality links, so as toachieve higher link capacity and a better coverage. The RN and a controlbase station (Donor E-UTRAN Node B; DeNB) that controls the RN areconnected through a radio S1 interface and X2 interface. When the DeNBacts as an agent between the RN and an MME, the DeNB forwards an S1message between the RN and the MME through the S1 interface, and whenthe DeNB acts as an agent between the RN and a base station adjacent tothe RN, the DeNB forwards an X2 message between the RN and the basestations adjacent to the RN through an X2 interface.

In a convention network, when no X2 interface is available between twoeNBs due to some reason, for example, when connection between the eNBsis interrupted due to external causes, if a UE is handed over from oneeNB to another eNB, handover needs to be performed through anS1interface connected to the MME, that is, a first eNB sends a handoverrequest to a second eNB through the MME. However, in a relay network,when no X2 interface is available between an eNB and a DeNB, if a UE ishanded over from the eNB to a RN that is controlled by the DeNB, as theMME cannot determine the DeNB corresponding to the RN, a handoverrequest cannot be correctly sent, causing that the handover processcannot be performed normally.

SUMMARY OF THE INVENTION

Embodiments of the present invention provide a handover method andsystem in a relay network, a relay node, a control base station and abase station, so as to implement a normal handover in a relay network.

An embodiment of the present invention provides a handover method in arelay network, where the method includes:

receiving, by a relay node, a first area identifier that identifies therelay node;

sending a system information broadcast message carrying the first areaidentifier to a terminal in a coverage area; and

receiving a handover request message, which is forwarded by a controlbase station according to the first area identifier, and performing,according to the handover request message, a control operation ofaccessing the relay node on the terminal.

An embodiment of the present invention further provides a handovermethod in a relay network, where the method includes:

sending, by a control base station, a response message to a relay nodeaccording to a received interface setup request message, where theresponse message carries a first area identifier that identifies therelay node and is allocated to the relay node; and

receiving a handover request message, which is sent by a mobilitymanagement entity according to the first area identifier, and forwardingthe handover request message to the relay node, so that the relay nodeperforms, according to the handover request message, a control operationof accessing the relay node on a terminal.

An embodiment of the present invention further provides a handovermethod in a relay network, where the method includes:

receiving, by a base station, a measurement report sent by a terminal,where the measurement report carries a first area identifier obtained bythe terminal from a system information broadcast message that isreceived from a relay node; and

sending a handover required message to a mobility management entityaccording to the first area identifier, so that the mobility managemententity sends, according to the first area identifier, a handover requestmessage to a control base station that controls the relay node, wherethe handover request message indicates that the terminal requests to behanded over from the base station to the relay node.

An embodiment of the present invention provides a relay node, including:

a first receiving module, configured to receive a first area identifierthat identifies a relay node and a handover request message that isforwarded by a control base station according to the first areaidentifier;

a first sending module, configured to send a system informationbroadcast message carrying the first area identifier that is received bythe first receiving module to a terminal in a coverage area; and

a processing module, configured to perform, according to the handoverrequest message that is received by the first receiving module, acontrol operation of accessing the relay node on the terminal.

An embodiment of the present invention provides a control base station,including:

a second sending module, configured to send a response message to arelay node according to a received interface setup request message,where the response message carries a first area identifier thatidentifies the relay node and is allocated to the relay node; and

a second receiving module, configured to receive a handover requestmessage sent by a mobility management entity according to the first areaidentifier, and forward the handover request message to the relay node.

An embodiment of the present invention provides a base station,including:

a third receiving module, configured to receive a measurement reportsent by a terminal, where the measurement report carries a first areaidentifier obtained by the terminal from a system information broadcastmessage that is received from a relay node; and

a third sending module, configured to send, according to the first areaidentifier, a handover required message to a mobility management entity,so that the mobility management entity sends, according to the firstarea identifier, a handover request message to a control base stationthat controls the relay node, where the handover request messageindicates that the terminal requests to be handed over from the basestation to the relay node.

An embodiment of the present invention provides a handover system in arelay network, where the system includes: a relay node, a control basestation, a base station and a mobility management entity.

The relay node is configured to receive a first area identifier thatidentifies the relay node; send a system information broadcast messagecarrying the first area identifier to a terminal in a coverage area;receive a handover request message, which is forwarded by the controlbase station according to the first area identifier; and perform,according to the handover request message, a control operation ofaccessing the relay node on the terminal.

The control base station is configured to send a response message to therelay node according to a received interface setup request message,where the response message carries the first area identifier thatidentifies the relay node and is allocated to the relay node; receive ahandover request message that is sent by the mobility management entityaccording to the first area identifier; and forward the handover requestmessage to the relay node, so that the relay node performs, according tothe handover request message, a control operation of accessing the relaynode on the terminal.

The base station is configured to receive a measurement report that issent by the terminal, where the measurement report carries the firstarea identifier obtained by the terminal from the system informationbroadcast message that is received from the relay node; according to thefirst area identifier, send a handover required message to the mobilitymanagement entity, so that the mobility management entity sends,according to the first area identifier, a handover request message tothe control base station that controls the relay node, where thehandover request message indicates that the terminal requests to behanded over from the base station to the relay node.

Through the handover method and system in a relay network, the relaynode, the control base station and the base station according to theembodiments of the present invention, the first area identifier thatidentifies the RN is allocated to the RN, a UE can be normally handedover from the eNB to the RN in a relay network.

BRIEF DESCRIPTION OF THE DRAWINGS

To illustrate the technical solutions in the embodiments of the presentinvention or in the prior art more clearly, the accompanying drawingsrequired for describing the embodiments or the prior art are introducedbelow briefly. Apparently, the accompanying drawings in the followingdescriptions merely show some of the embodiments of the presentinvention, and persons of ordinary skill in the art may further obtainother drawings according to these accompanying drawings without creativeefforts.

FIG. 1 is a flow chart of an embodiment of a handover method in a relaynetwork according to the present invention;

FIG. 2 is a flow chart of an embodiment of another handover method in arelay network according to the present invention;

FIG. 3 is a flow chart of an embodiment of still another handover methodin a relay network according to the present invention;

FIG. 4 is a flow chart of an embodiment of still another handover methodin a relay network according to the present invention;

FIG. 5 is a flow chart of an embodiment of still another handover methodin a relay network according to the present invention;

FIG. 6 is a flow chart of an embodiment of still another handover methodin a relay network according to the present invention;

FIG. 7 is a flow chart of an embodiment of still another handover methodin a relay network according to the present invention;

FIG. 8 is a flow chart of an embodiment of still another handover methodin a relay network according to the present invention;

FIG. 9 is a flow chart of an embodiment of still another handover methodin a relay network according to the present invention;

FIG. 10 is a flow chart of an embodiment of a handover method in a relaynetwork according to the present invention;

FIG. 11 is a flow chart of an embodiment of a handover method in a relaynetwork according to the present invention;

FIG. 12 is a flow chart of an embodiment of a handover method in a relaynetwork according to the present invention;

FIG. 13 is a flow chart of an embodiment of a handover method in a relaynetwork according to the present invention;

FIG. 14 is a schematic structural diagram of an embodiment of a relaynode according to the present invention;

FIG. 15 is a schematic structural diagram of an embodiment of a controlbase station according to the present invention;

FIG. 16 is a schematic structural diagram of an embodiment of a basestation according to the present invention; and

FIG. 17 is a block diagram of an embodiment of a handover system in arelay network according to the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

In order to make the objectives, technical solutions, and advantages ofthe embodiments of the present invention more comprehensible, thetechnical solutions in the embodiments of the present invention will beclearly and completely described in the following with reference to theaccompanying drawings. It is obvious that the embodiments to bedescribed are only a part rather than all of the embodiments of thepresent invention. All other embodiments obtained by persons skilled inthe art based on the embodiments of the present invention withoutcreative efforts shall fall within the protection scope of the presentinvention.

FIG. 1 is a flow chart of an embodiment of a handover method in a relaynetwork according to the present invention. As shown in FIG. 1, thehandover method in a relay network provided by an embodiment of thepresent invention includes the following:

Step 101: An RN receives a first area identifier that identifies the RN.

Step 102: The RN sends a system information broadcast message carryingthe first area identifier to a UE in a coverage area.

Step 103: The RN receives a handover request message, which is forwardedby a DeNB according to the first area identifier, and performs,according to the handover request message, a control operation ofaccessing the RN on the UE.

In the embodiment of the present invention, when an interface is setupbetween the RN and the DeNB, the DeNB allocates the first areaidentifier to the RN. For example, the first area identifier may be afirst evolved universal terrestrial radio access network cell globalidentifier (EUTRAN Cell Global Identifier; ECGI) or a first trackingarea identity (Tracking Area Identity; TAI), and so on. After receivingthe first area identifier allocated by the DeNB, the RN sends a systeminformation broadcast message carrying the first area identifier to allUEs in the coverage area. When a certain UE that is in a connectionstate moves from a cell of an eNB to a cell of the RN, the UE receivesthe system information broadcast message that carries the first areaidentifier and is sent by the RN, and reports the system informationbroadcast message to the eNB. In this embodiment, the eNB or an MME mayfurther obtain an identifier of the DeNB (DeNB_ID) according to thefirst area identifier, so the eNB can further send a handover requestmessage of handing over from the eNB to the RN to a DeNB of the RNthrough the MME. After receiving the handover request message forwardedby the DeNB, the RN performs, according to the handover request message,a control operation of accessing the RN on the UE.

Through the handover method in a relay network according to theembodiment of the present invention, when an interface is set up betweenthe RN and the DeNB, the DeNB allocates a first area identifier thatidentifies the RN to the RN, so that the UE can be normally handed overfrom the eNB to the RN in the relay network.

FIG. 2 is a flow chart of an embodiment of another handover method in arelay network according to the present invention. As shown in FIG. 2,the method provided by an embodiment of the present invention mayinclude the following:

Step 201: An RN receives a response message for an interface setuprequest message of a DeNB, where the response message carries a firstECGI allocated by the DeNB.

The interface setup request message includes an X2 interface setuprequest message, and the response message includes an X2 responsemessage corresponding to the X2 interface setup request message. Thefirst ECGI includes an identifier of the DeNB (DeNB_ID).

Step 202: The RN sends a system information broadcast message carryingthe first ECGI to a UE in a coverage area.

Step 203: The RN receives a handover request message that carries thefirst ECGI and is forwarded by the DeNB, and performs, according to thefirst ECGI, a control operation of accessing the RN on the UE.

In the embodiment of the present invention, when an X2 interface is setup between the RN and the DeNB, the DeNB allocates the first ECGI to theRN. After receiving the first ECGI allocated by the DeNB, the RN sends asystem information broadcast message carrying the first ECGI to all UEsin the coverage area. When a certain UE that is in a connection statemoves from a cell of an eNB to a cell of the RN, the UE receives thesystem information broadcast message that carries the first ECGI and issent by the RN, and reports the system information broadcast message tothe eNB; and the eNB further sends the handover request message ofhanding over from the eNB to the RN to a DeNB of the RN through the MME.Because the first ECGI is allocated by the DeNB, the first 20 bitsrepresent an identifier of the DeNB (DeNB_ID), so the eNB or the MME canobtain the DeNB_ID according to the first ECGI, and the eNB sends thehandover request message to the DeNB through the MME. After receivingthe handover request message forwarded by the DeNB, the RN performs,according to the handover request message, a control operation ofaccessing the RN on the UE.

Through the handover method in a relay network according to theembodiment of the present invention, when an interface is set up betweenthe RN and the DeNB, the DeNB allocates a first ECGI that identifies theRN to the RN, so that the eNB can obtain the DeNB_ID according to thefirst ECGI and the UE can be normally handed over from the eNB to the RNin the relay network.

FIG. 3 is a flow chart of an embodiment of another handover method in arelay network according to the present invention. As shown in FIG. 3, anembodiment of the present invention provides a handover method in arelay network, which includes the following:

Step 301: An RN receives a response message for an interface setuprequest message of a DeNB, where the response message carries a firstTAI allocated by the DeNB.

The interface setup request message includes an X2 interface setuprequest message or an S1 interface setup request message, and the X2interface setup request message carries a third ECGI to be reported tothe DeNB. The response message includes an X2 response messagecorresponding to the X2 interface setup request message or an S1response message corresponding to the S1 interface setup requestmessage. The first TAI is corresponding to a DeNB_ID uniquely.

Step 302: The RN sends a system information broadcast message carryingthe first TAI to a UE in a coverage area, where the system informationbroadcast message further carries a third ECGI.

Step 303: The RN receives a handover request message that carries thethird ECGI and is forwarded by the DeNB, and performs, according to thethird ECGI, a control operation of accessing the RN on the UE.

In the embodiment of the present invention, when an X2 interface is setup between the RN and the DeNB, the RN reports the third ECGI to theDeNB. When an S1 interface is set up between the RN and the DeNB, theDeNB allocates the first TAI to the RN, and the following principles arefollowed when the DeNB allocates the first TAI to the RN: different TAIsare allocated to RNs under different DeNBs, and no TAI shared by DeNBsis allocated to the RN. After receiving the first TAI allocated by theDeNB, the RN sends a system information broadcast message carrying thefirst TAI and the third ECGI to all UEs in the coverage area. When acertain

UE that is in a connection state moves from a cell of an eNB to a cellof the RN, the UE receives the system information broadcast message thatcarries the first TAI and the third ECGI and is sent by the RN, andreports the system information broadcast message to the eNB; and the eNBfurther sends the handover request message of handing over from the eNBto the RN to a DeNB of the RN through the MME. Because the first TAI iscorresponding to a DeNB_ID uniquely, the MME can obtain the DeNB_IDaccording to the first TAI, and send the handover request message to theDeNB. After receiving the handover request message forwarded by theDeNB, the RN performs, according to the handover request message, acontrol operation of accessing the RN on the UE.

Through the handover method in a relay network according to theembodiment of the present invention, when an interface is set up betweenthe RN and the DeNB, the DeNB allocates a first TAI that identifies theRN to the RN, so that the MME can obtain the DeNB_ID according to thefirst TAI, and the UE can be normally handed over from the eNB to the RNin the relay network.

FIG. 4 is a flow chart of an embodiment of still another handover methodin a relay network according to the present invention. As shown in FIG.4, an embodiment of the present invention provides a handover method ina relay network, which includes the following:

Step 401: An RN receives a system information broadcast message thatcarries a second ECGI identifying the DeNB and is sent by a DeNB.

Step 402: The RN sends a configuration request message carrying thesecond ECGI to an operation administration and maintenance (OperationAdministration and Maintenance; OAM) apparatus.

Step 403: The RN receives a configuration response message that carriesa first area identifier and is returned by the OAM apparatus accordingto the second ECGI, where the first area identifier is a first ECGIincluding DeNB_ID.

Step 404: The RN sends a system information broadcast message carrying afirst ECGI to a UE in a coverage area.

Step 405: The RN receives a handover request message that carries thefirst ECGI and is forwarded by the DeNB, and performs, according to thefirst ECGI, a control operation of accessing the RN on the UE.

Step 404-step 405 in this embodiment are the same as step 202-step 203in the method embodiment shown in FIG. 2, and the difference lies inthat, in this embodiment, before an interface is set up between the RNand the DeNB, the RN first receives the system information broadcastmessage that carries the second ECGI and is sent by the DeNB, and thensends a configuration request message carrying the second ECGI to theOAM apparatus, and the OAM apparatus allocates a first ECGI that is notused by the DeNB to the RN according to the second ECGI that identifiesthe DeNB, so as to identify the RN. Or, when the RN receives the systeminformation broadcast message that carries the second ECGI and is sentby the DeNB, because the first 20 bits of the second ECGI represent theDeNBID, the RN may directly obtain the DeNB_ID, and send theconfiguration request message carrying the DeNB_ID to the OAM apparatus,and the OAM apparatus allocates the first ECGI that is not used by theDeNB to the RN according to the DeNB_ID, so as to identify the RN.

Through the handover method in a relay network according to theembodiment of the present invention, before an interface is set upbetween the RN and the DeNB, the OAM apparatus allocates the first ECGIthat identifies the RN for the RN, so that the UE can be normally handedover from an eNB to the RN in the relay network.

FIG. 5 is a flow chart of an embodiment of still another handover methodin a relay network according to the present invention. As shown in FIG.5, an embodiment of the present invention provides a handover method ina relay network, which includes the following:

Step 501: An RN receives a system information broadcast message thatcarries a second ECGI identifying the DeNB and is sent by a DeNB.

Step 502: The RN sends a configuration request message carrying thesecond ECGI to an OAM apparatus.

Step 503: The RN receives a configuration response message that carriesa first area identifier and is returned by the OAM apparatus accordingto the second ECGI, where the first area identifier is a first TAIcorresponding to a DeNB_ID uniquely.

Step 504: The RN sends a system information broadcast message carryingthe first TAI to a UE in a coverage area, where the system informationbroadcast message further carries a third ECGI to be reported to theDeNB by the RN.

Step 505: The RN receives a handover request message that carries thethird ECGI and is forwarded by the DeNB, and performs, according to thethird ECGI, a control operation of accessing the RN on the UE.

Step 504-step 505 in this embodiment are the same as step 302-step 303in the method embodiment shown in FIG. 3, and the difference lies inthat, in this embodiment, before an interface is set up between the RNand the DeNB, the RN first receives the system information broadcastmessage that carries the second ECGI and is sent by the DeNB, and thensends the configuration request message carrying the second ECGI to theOAM apparatus, and the OAM apparatus allocates the first TAI to the RNaccording to the second ECGI that identifies the DeNB. Or, when the RNreceives the system information broadcast message that carries thesecond ECGI and is sent by the DeNB, because the first 20 bits of thesecond ECGI represent the DeNB_ID, the RN may directly obtain theDeNB_ID, and send the configuration request message carrying the DeNB_IDto the OAM apparatus, and the OAM apparatus allocates the first TAI tothe RN according to the DeNB_ID. In the two cases above, the followingprinciples are followed when the OAM allocates the first TAI to the RN:different TAIs are allocated to RNs under different DeNBs, and no TAIshared by DeNBs is allocated to the RN. The first TAI allocatedfollowing this principle is corresponding to a DeNB_ID uniquely, so anMME can obtain the DeNB_ID according to the first TAI, and send thehandover request message to the DeNB.

Through the handover method in a relay network according to theembodiment of the present invention, before an interface is set upbetween the RN and the DeNB, the OAM apparatus allocates the first TAIuniquely corresponding to a DeNB to the RN, so that the UE can benormally handed over from an eNB to the RN in the relay network.

FIG. 6 is a flow chart of an embodiment of still another handover methodin a relay network according to the present invention. As shown in FIG.6, an embodiment of the present invention provides a handover method ina relay network, which includes the following:

Step 601: A DeNB sends a response message to an RN according to areceived interface setup request message, where the response messagecarries a first area identifier that identifies the RN and is allocatedto the RN.

Step 602: The DeNB receives a handover request message sent by an MMEaccording to the first area identifier, and forwards the handoverrequest message to the RN, so that the RN performs, according to thehandover request message, a control operation of accessing the RN on theUE.

In the embodiment of the present invention, when an interface is set upbetween the RN and the DeNB, the DeNB allocates the first areaidentifier to the RN, for example, the first area identifier may be afirst ECGI or a first TAI. After receiving the first area identifierallocated by the DeNB, the RN sends a system information broadcastmessage carrying the first area identifier to all UEs in a coveragearea. When a certain UE that is in a connection state moves from a cellof an eNB to a cell of the RN, the UE receives the system informationbroadcast message carrying the first area identifier, and reports thesystem information broadcast message to the eNB. In this embodiment, theeNB or the MME may obtain DeNB_ID according to the first areaidentifier, so the eNB can further send the handover request message ofhanding over from the eNB to the RN to a DeNB of the RN through the MME.After receiving the handover request message sent by the MME, the DeNBforwards the handover request message to the RN, so that the RNperforms, according to the handover request message, a control operationof accessing the RN on the UE.

Through the handover method in a relay network according to theembodiment of the present invention, when an interface is set up betweenthe RN and the DeNB, the DeNB allocates a first area identifier thatidentifies the RN to the RN, so that the UE can be normally handed overfrom the eNB to the RN in the relay network.

Further, the interface setup request message includes an X2 interfacesetup request message. The response message includes an X2 responsemessage corresponding to the X2 interface setup request message. Theallocated first area identifier is a first ECGI carried in the X2response message, and the first ECGI includes an identifier of the DeNB(DeNB_ID).

In the embodiment of the present invention, when an X2 interface is setup between the RN and the DeNB, the DeNB allocates the first ECGI to theRN. After receiving the first ECGI allocated by the DeNB, the RN sends asystem information broadcast message carrying the first ECGI to all UEsin the coverage area. When a certain UE that is in a connection statemoves from a cell of the eNB to a cell of the RN, the UE receives thesystem information broadcast message that carries the first ECGI and issent by the RN, and reports the system information broadcast message tothe eNB; and eNB further sends a handover request message of handingover from the eNB to the RN to a DeNB of the RN through the MME. Becausethe first ECGI is allocated by the DeNB, and the first 20 bits representthe DeNB_ID, the eNB or the MME can obtain the DeNB_ID according to thefirst ECGI, and the eNB sends the handover request message to the DeNBthrough the MME. After receiving the handover request message sent bythe MME, the DeNB forwards the handover request message to the RN, sothat the RN performs, according to the handover request message, acontrol operation of accessing the RN on the UE.

Further, the interface setup request message includes an X2 interfacesetup request message and an S1 interface setup request message, and theX2 interface setup request message carries the a third ECGI to bereported to the DeNB. The response message includes an X2 responsemessage corresponding to the X2 interface setup request message and anS1 response message corresponding to the S1 interface setup requestmessage. The allocated first area identifier is a first TAI carried inthe S1 response message, and the first TAI is corresponding to a DeNB_IDuniquely. Meanwhile, after receiving the response message sent by theRN, the DeNB may further send a base station configuration updatemessage to the MME, where the base station configuration update messagecarries the first TAI, and is used to enable the MME to obtain acorresponding relationship between the first TAI and the DeNBID, sothat, when the MME receives the handover required message carrying thefirst TAI, the MME can obtain the corresponding DeNB_ID according to thefirst TAI.

In the embodiment of the present invention, when an X2 interface is setup between the RN and the DeNB, the RN reports the third ECGI to theDeNB. When an S1 interface is set up between the RN and the DeNB, theDeNB allocates the first TAI to the RN, and the following principles arefollowed when the DeNB allocates the first TAI to the RN: different TAIsare allocated to RNs under different DeNBs, and no TAI shared by DeNBsis allocated to the RN. After receiving the first TAI allocated by theDeNB, the RN sends a system information broadcast message carrying thefirst TAI and the third ECGI to all UEs in the coverage area. When acertain UE that is in a connection state moves from a cell of the eNB toa cell of the RN, the UE receives the system information broadcastmessage that carries the first TAI and the third ECGI and is sent by theRN, and reports the system information broadcast message to the eNB; andthe eNB further sends the handover request message of handing over fromthe eNB to the RN to a DeNB of the RN through the MME. Because the firstTAI is corresponding to a DeNB_ID uniquely, the MME can obtain theDeNB_ID according to the first TAI, and send the handover requestmessage to the DeNB. After receiving the handover request message sentby the MME, the DeNB forwards the handover request message to the RN, sothat the RN performs, according to the handover request message, acontrol operation of accessing the RN on the UE.

Through the handover method in a relay network according to theembodiment of the present invention, when an interface is set up betweenthe RN and the DeNB, the DeNB allocates a first ECGI or a first TAI thatidentifiers the RN to the RN, so that the MME can obtain the DeNB_IDaccording to the first ECGI or the first TAI, so that the UE can benormally handed over from the eNB to the RN in the relay network.

FIG. 7 is a flow chart of an embodiment of still another handover methodin a relay network according to the present invention. As shown in FIG.7, an embodiment of the present invention provides a handover method ina relay network, which includes the following:

Step 701: An eNB receives a measurement report sent by a UE, where themeasurement report carries a first area identifier obtained by the UEfrom a system information broadcast message received from an RN.

Step 702: The eNB sends a handover required message to an MME accordingto the first area identifier, so that the MME sends a handover requestmessage to a DeNB that controls the RN according to the first areaidentifier, where the handover request message indicates that the UErequests to be handed over from the eNB to the RN.

In the embodiment of the present invention, when an interface is set upbetween the RN and the DeNB, the DeNB allocates the first areaidentifier to the RN. For example, the first area identifier may be afirst ECGI or a first TAI, and so on. After receiving the first areaidentifier allocated by the DeNB, the RN sends a system informationbroadcast message carrying the first area identifier to all UEs in acoverage area. When a certain UE that is in a connection state movesfrom a cell of the eNB to a cell of the RN, the UE receives the systeminformation broadcast message that carries the first area identifier andis sent by the RN, and further sends a measurement report to the eNB,where the measurement report carries the first area identifier obtainedby the UE from the system information broadcast message received fromthe RN; and in this embodiment, the eNB or the MME may obtain theDeNB_ID according to the first area identifier, so the eNB sends ahandover required message to the MME, so that the MME can send thehandover request message of handing over from the eNB to the RN to theDeNB of the RN. After receiving the handover request message forwardedby the DeNB, the RN performs, according to the handover request message,a control operation of accessing the RN on the UE.

Through the handover method in a relay network according to theembodiment of the present invention, the first area identifier thatidentifies the RN is allocated to the RN, so that the UE can be normallyhanded over from the eNB to the RN in the relay network.

FIG. 8 is a flow chart of an embodiment of still another handover methodin a relay network according to the present invention. As shown in FIG.8, an embodiment of the present invention further provides a handovermethod in a relay network, which includes the following:

Step 801: An eNB receives a measurement report sent by a UE, where themeasurement report carries a first ECGI obtained by the UE from a systeminformation broadcast message received from an RN, and the first ECGIincludes DeNB_ID.

Step 802: The eNB obtains the DeNB_ID according to the first ECGIcarried in the measurement report.

Step 803: The eNB sends a handover required message to an MME, where thehandover required message carries the DeNB_ID and the first ECGI, sothat the MME sends a handover request message to a DeNB that controlsthe RN according to the handover required message, where the handoverrequest message carries the first ECGI and indicates that the UErequests to be handed over from the eNB to the RN.

In the embodiment of the present invention, when an X2 interface is setup between the RN and the DeNB, the DeNB allocates the first ECGI to theRN. After receiving the first ECGI allocated by the DeNB, the RN sends asystem information broadcast message carrying the first ECGI to all UEsin a coverage area. When a certain HE that is in a connection statemoves from a cell of the eNB to a cell of the RN, the UE receives thesystem information broadcast message that carries the first ECGI and issent by the RN, and further sends a measurement report to the eNB, wherethe measurement report carries the first ECGI obtained by the UE fromthe system information broadcast message received from the RN; and theeNB obtains the DeNB_ID according to the first ECGI, and then sends ahandover required message to the MME, where the handover requiredmessage carries the DeNB_ID and the first ECGI, so that the MME sendsthe handover request message of handing over from the eNB to the RN tothe DeNB of the RN. Because the first ECGI is allocated by the DeNB, andthe first 20 bits represent the DeNB_ID, the eNB can obtain the DeNB_IDaccording to the first ECGI, and send the handover request message tothe DeNB through the MME. After receiving the handover request messageforwarded by the DeNB, the RN performs, according to the handoverrequest message, a control operation of accessing the RN on the UE.

Or, the eNB may also directly send a handover required message carryingthe first ECGI to the MME, and then the MME obtains the DeNB_ID includedin the handover required message according to the first ECGI, andperforms subsequent operations.

Through the handover method in a relay network according to theembodiment of the present invention, the first ECGI that identifies theRN is allocated to the RN, so that the eNB can obtain the DeNB_IDaccording to the first ECGI, and the UE can be normally handed over fromthe eNB to the RN in the relay network.

FIG. 9 is a flow chart of an embodiment of still another handover methodin a relay network according to the present invention. As shown in FIG.9, an embodiment of the present invention provides a handover method ina relay network, which includes the following:

Step 901: An eNB receives a measurement report sent by a UE, where themeasurement report carries a third ECGI and a first TAI that areobtained by the UE from a system information broadcast message receivedfrom an RN, and the first TAI is corresponding to a DeNB_ID uniquely.

Step 902: The eNB sends a handover required message to an MME accordingto the measurement report, where the handover required message carriesthe third ECGI and the first TAI, so that the MME obtains the DeNB_IDaccording to the first TAI, and sends a handover request message to theDeNB, where the handover request message carries the third ECGI andindicates that the UE requests to be handed over from the eNB to the RN.

In the embodiment of the present invention, when an X2 interface is setup between the RN and the DeNB, the RN reports the third ECGI to theDeNB. When an S1 interface is set up between the RN and the DeNB, theDeNB allocates the first TAI to the RN, and the following principles arefollowed when the DeNB allocates the first TAI to the RN: different TAIsare allocated to RNs under different DeNBs, and no TAI shared by DeNBsis allocated to the RN. After receiving the first TAI allocated by theDeNB, the RN sends a system information broadcast message carrying thefirst TAI and the third ECGI to all UEs in a converge area. When acertain UE that is in a connection state moves from a cell of the eNB toa cell of the RN, the UE receives a system information broadcast messagethat carries the first TAI and the third ECGI and is sent by the RN, andfurther sends a measurement report to the eNB, where the measurementreport carries the third ECGI and the first TAI that are obtained by theUE from the system information broadcast message received from the RN;and the eNB sends a handover required message to the MME according tothe measurement report, where the handover required message carries thethird ECGI and the first TAI, so that the MME obtains the DeNB_IDaccording to the first TAI, and sends the handover request message ofhanding over from the eNB to the RN to the DeNB. Because the first TAIis corresponding to a DeNB_ID uniquely, the MME can obtain the DeNB_IDaccording to the first TAI, and send the handover request messagecarrying the third ECGI to the DeNB. After receiving the handoverrequest message forwarded by the DeNB, the RN performs, according to thehandover request message, a control operation of accessing the RN on theUE.

Through the handover method in a relay network according to theembodiment of the present invention, the first TAI that identifies theRN is allocated to the RN, so that the MME can obtain the DeNB_IDaccording to the first TAI, and the UE can be normally handed over fromthe eNB to the RN in the relay network.

FIG. 10 is a flow chart of an embodiment of a handover method in a relaynetwork according to the present invention. As shown in FIG. 10, anembodiment of the present invention provides a handover method in arelay network, which specifically includes the following:

Step 1001: An RN sends an X2 interface setup request message(“X2_Setup_Request(RN_ID, . . . )”) carrying an identifier of the RN(RN_ID) to a DeNB.

Step 1002: The DeNB returns a response message(“X2_Setup_Response(DeNB_ID,ECGI_y, . . . )”) carrying DeNB_ID and afirst ECGI that is allocated by the DeNB.

Step 1003: The RN sends an S1 interface setup request message(“S1_Setup_Request(RN_ID, . . . )”) carrying the RN_ID to the DeNB.

Step 1004: The DeNB returns a response message (“S1_Setup_Response( . .. )”) to the RN;

Step 1005: When a UE that is in a connection state moves from a cell ofan eNB to a cell of the RN, the UE receives a system informationbroadcast (System Information Broadcast; SIB) message (“SIB(ECGI_y, . .. )”) that carries the first ECGI and is sent by the RN to all UEs in acoverage area.

Step 1006: The UE sends a measurement report(“Measurement_Report(ECGI_y, . . . )”) carrying the first ECGI to theeNB.

Step 1007: The eNB obtains the DeNB_ID according to the measurementreport;

Step 1008: The eNB sends a handover required message(“Handover_Required(DeNB_ID,ECGI_y, . . . )”) carrying the DeNB_ID andthe first ECGI to the MME.

Step 1009: The MME sends a handover request message(“Handover_Request(ECGI_y, . . . )”) carrying the first ECGI to acorresponding DeNB according to the DeNB_ID.

Step 1010: The DeNB forwards the handover request message to the RN.

Step 1011: The RN performs a control operation of accessing the RN onthe UE.

Through the handover method in a relay network according to theembodiment of the present invention, when an interface is set up betweenthe RN and the DeNB, the DeNB allocates the first ECGI that identifiesthe RN to the RN, so that the eNB can obtain the DeNB_ID according tothe first ECGI, and the UE can be normally handed over from the eNB tothe RN in the relay network.

FIG. 11 is a flow chart of an embodiment of a handover method in a relaynetwork according to the present invention. As shown in FIG. 11, anembodiment of the present invention provides a handover method in arelay network, which specifically includes the following:

Step 1101: An RN sends an X2 interface setup request message(“X2_Setup_Request(RN_ID, ECGI_y, . . . )”) carrying RN_ID and a thirdECGI to a DeNB.

Step 1102: The DeNB returns a response message(“X2_Setup_Response(DeNB_ID, . . . )”) carrying DeNB_ID.

Step 1103: The RN sends an S1 interface setup request message(“S1_Setup_Request(RN_ID, . . . )”) carrying the RN_ID to the DeNB.

Step 1104: The DeNB returns a response message(“S1_Setup_Response(TAI_y, . . . )”) carrying a first TAI to the RN, andsends a base station configuration update message(“eNB_Configuration_Update(TAI_y, . . . )”) carrying the first TAI to anMME.

Step 1105: When a UE that is in a connection state moves from a cell ofan eNB to a cell of the RN, the UE receives a SIB message(“SIB(ECGI_y,TAI_y, . . . )”) that carries the third ECGI and the firstTAI and is sent by the RN to all UEs in a coverage area.

Step 1106: The UE sends a measurement report(“Measurement_Report(ECGI_y,TAI_y, . . . )”) carrying the third ECGI andthe first TAI to the eNB;

Step 1107: The eNB sends a handover required message(“Handover_Required(RN_ID,TAI_y,ECGI_y, . . . )”) carrying the RN_ID,the first TAI and the third ECGI to the MME.

Step 1108: The MME obtains the DeNB_ID according to the TAI_y.

Step 1109: The MME sends, according to the DeNB_ID, a handover requestmessage (“Handover_Request(ECGI_y, . . . )”) carrying the third ECGI tothe DeNB that controls the RN.

Step 1110: The DeNB forwards the handover request message to the RN.

Step 1111: The RN performs a control operation of accessing the RN onthe UE.

Through the handover method in a relay network according to theembodiment of the present invention, when an interface is set up betweenthe RN and the DeNB, the DeNB allocates the first TAI uniquelycorresponding to a DeNB to the RN, so that the MME can obtain theDeNB_ID according to the first TAI, and the UE can be normally handedover from the eNB to the RN in the relay network.

FIG. 12 is a flow chart of an embodiment of a handover method in a relaynetwork according to the present invention. As shown in FIG. 12, anembodiment of the present invention provides a handover method in arelay network, which specifically includes the following:

Step 1201: An RN receives a SIB message (“SIB(ECGI_x, . . . )”) thatcarries a second ECGI identifying a DeNB and is sent by the DeNB.

Step 1202: The RN sends a configuration request message(“RN_Configuration_Request(ECGI_x, . . . )”) carrying the second ECGI toan OAM apparatus.

Step 1203: The OAM apparatus returns a configuration response message(“RN_Configuration_Response(ECGI_y, . . . )”) carrying a first ECGI tothe RN.

Step 1204: The RN sends an X2 interface setup request message

(“X2_Setup_Request(RN_ID, ECGI_y, . . . )”) carrying RN_ID and the firstECGI to the DeNB.

Step 1205: The DeNB returns a response message(“X2_Setup_Response(DeNB_ID, . . . )”) carrying DeNB_ID.

For steps 1206-1214, see steps 1003-1011.

Through the handover method in a relay network according to theembodiment of the present invention, before an interface is set upbetween the RN and the DeNB, the OAM apparatus allocates the first ECGIthat includes the DeNB_ID and is not used by the DeNB to the RN, so thatthe UE can be normally handed over from the eNB to the RN in the relaynetwork.

FIG. 13 is a flow chart of an embodiment of a handover method in a relaynetwork according to the present invention. As shown in FIG. 13, anembodiment of the present invention provides a handover method in arelay network, which specifically includes the following:

Step 1301: An RN receives a SIB message (“SIB(ECGI_x, . . . )”) thatcarries a second ECGI identifying a DeNB and is sent by the DeNB.

Step 1302: The RN sends a configuration request message(“RN_Configuration_Request(ECGI_x, . . . )”) carrying the second ECGI toan OAM apparatus.

Step 1303: The OAM apparatus returns a configuration response message(“RN_Configuration_Response(TAI_y, . . . )”) carrying a first TAI to theRN.

Step 1304: The RN sends an X2 interface setup request message(“X2_Setup_Request(RN_ID, ECGI_y, . . . )”) carrying RN_ID and a thirdECGI to the DeNB.

Step 1305: The DeNB returns a response message(“X2_Setup_Response(DeNB_ID, . . . )”) carrying DeNB_ID.

Step 1306: The RN sends an S1 interface setup request message(“S1_Setup_Request(RN_ID,TAI_y, . . . )”) carrying the RN_ID and thefirst TAI to the DeNB.

Step 1307: The DeNB returns a response message (“S1_Setup_Response( . .. )”) to the RN, and sends a base station configuration update message(“eNB_Configuration_Update(TAI_y, . . . )”) carrying the first TAI to anMME.

For steps 1308-1314, see steps 1105-1111.

Through the handover method in a relay network according to theembodiment of the present invention, before an interface is set upbetween the RN and the DeNB, the OAM apparatus allocates the first TAIuniquely corresponding to a DeNB to the RN, so that the UE can benormally handed over from the eNB to the RN in the relay network.

FIG. 14 is a schematic structural diagram of an embodiment of a relaynode according to the present invention. As shown in FIG. 14, anembodiment of the present invention provides a relay node, including: afirst receiving module 1401, a first sending module 1402 and aprocessing module 1403. The first receiving module 1401 is configured toreceive a first area identifier that identifies the relay node and ahandover request message that is forwarded by the DeNB according to thefirst area identifier. The first sending module 1402 is configured tosend a system information broadcast message carrying first areaidentifier that is received by the first receiving module 1401 to UEs ina coverage area. The processing module 1403 is configured to perform,according to the handover request message received by the firstreceiving module 1401, a control operation of accessing the relay nodeon the UE.

Specifically, the first receiving module 1401 is further configured toreceive a response message of the DeNB for an interface setup requestmessage, where the response message carries the first area identifierallocated by the DeNB. The interface setup request message includes anX2interface setup request message. The response message includes an X2response message corresponding to the X2 interface setup requestmessage. The first area identifier allocated by the DeNB is a first ECGIcarried in the X2 response message, and the first ECGI includes DeNB_ID.

Or, the interface setup request message includes an X2 interface setuprequest message and an S1 interface setup request message, and the X2interface setup request message carries the a third ECGI to be reportedto the DeNB. The response message includes an X2 response messagecorresponding to the X2 interface setup request message and an S1response message corresponding to the S1 interface setup requestmessage. The first area identifier allocated by the DeNB is a first TAIcarried in the S1 response message, and the first TAI is correspondingto a DeNB_ID uniquely.

In addition, the first receiving module 1401 may further be configuredto receive a system information broadcast message that carries a secondECGI that identifies the DeNB and is sent by the DeNB; send aconfiguration request message carrying the second ECGI to an OAMapparatus; and receive a configuration response message that carries thefirst area identifier and is returned by the OAM apparatus according tothe second ECGI, where the first area identifier is a first ECGIincluding the DeNB_ID or a first TAI uniquely corresponding to aDeNB_ID.

Through the relay node according to the embodiment of the presentinvention, a first area identifier that identifies the RN is allocatedto the RN, so that the UE can be normally handed over from the eNB tothe RN in the relay network.

FIG. 15 is a schematic structural diagram of an embodiment of a controlbase station according to the present invention. As shown in FIG. 15, anembodiment of the present invention provides a control base station,including: a second sending module 1501 and a second receiving module1502. The second sending module 1501 is configured to send a responsemessage to an RN according to a received interface setup requestmessage, where the response message carries a first area identifier thatidentifies the RN and is allocated to the RN. The second receivingmodule 1502 is configured to receive a handover request message that issent by an MME according to the first area identifier, and forward thehandover request message to the RN, so that the RN performs, accordingto the handover request message, a control operation of accessing the RNon the UE.

Further, the interface setup request message includes an X2 interfacesetup request message, and the response message includes an X2 responsemessage corresponding to the X2interface setup request message. Theallocated first area identifier is a first ECGI carried in theX2response message, and the first ECGI includes an identifier of theDeNB (DeNB_ID).

Or, the interface setup request message includes an X2 interface setuprequest message and an S1 interface setup request message, and the X2interface setup request message carries a third ECGI to be reported tothe DeNB. The response message includes an X2 response messagecorresponding to the X2 interface setup request message and an S1response message corresponding to the S1 interface setup requestmessage. The allocated first area identifier is a first TAI carried inthe S1 response message, and the first TAI is corresponding to anidentifier of the DeNB (DeNB_ID) uniquely.

Further, the second sending module 1501 may be further configured tosend a base station configuration update message to the MME, where thebase station configuration update message carries a first areaidentifier, and the first area identifier is a first TAI carried in theS1response message, and the first TAI is corresponding to a DeNB_IDuniquely.

Through the control base station according to the embodiment of thepresent invention, a first area identifier that identifies the RN isallocated to the RN, so that the UE can be normally handed over from theeNB to the RN in the relay network.

FIG. 16 is a schematic structural diagram of an embodiment of a basestation according to the present invention. As shown in FIG. 16, anembodiment of the present invention provides a base station, including:a third receiving module 1601 and a third sending module 1602. The thirdreceiving module 1601 is configured to receive a measurement report sentby a UE, where the measurement report carries a first area identifierobtained by the UE from a system information broadcast message that isreceived from an RN. The third sending module 1602 is configured to senda handover required message to an MME according to the first areaidentifier, so that the MME sends, according to the first areaidentifier, a handover request message to a DeNB that controls the RN,where the handover request message indicates that the UE requests to behanded over from the base station to the RN.

Further, the first area identifier carried in the measurement report isa first ECGI, and the first ECGI includes DeNB_ID. At this time, thethird sending module 1602 is further configured to obtain, according tothe first ECGI carried in the measurement report, the DeNB_ID, and senda handover required message to the MME, where the handover requiredmessage carries the DeNB_ID and the first ECGI; or, the third sendingmodule 1602 is configured to directly send a handover required messageto the MME, where the handover required message carries the first ECGI,so that the MME obtains the DeNB_ID according to the first ECGI.

Further, the first area identifier carried in the measurement report isa first TAI, and the first TAI is corresponding to a DeNB_ID uniquely.At this time, the third sending module 1602 is further configured tosend a handover required message to the MME, where the handover requiredmessage carries the third ECGI and the first TAI, so that the MMEobtains the DeNB_ID according to the first TAI, and sends a handoverrequest message carrying the third ECGI to the DeNB.

Through the base station according to the embodiment of the presentinvention, a first area identifier that identifies the RN is allocatedto the RN, so that the UE can be normally handed over from the eNB tothe RN in the relay network.

FIG. 17 is a block diagram of an embodiment of a handover system in arelay network. As shown in FIG. 17, an embodiment of the presentinvention provides a handover system in a relay network, including: arelay node 1701, a control base station 1702, a base station 1703 and amobility management entity 1704. The relay node 1701 is configured toreceive a first area identifier that identifies the relay node 1701;send a system information broadcast message carrying the first areaidentifier to a UE in a coverage area; receive a handover requestmessage, which is forwarded by the control base station 1702 accordingto the first area identifier; and perform, according to the handoverrequest message, a control operation of accessing the relay node 1701 onthe UE. The control base station 1702 is configured to send a responsemessage to the relay node 1701 according to a received interface setuprequest message, where the response message carries the first areaidentifier that identifies the relay node 1701 and is allocated to therelay node 1701; receive a handover request message that is sent by themobility management entity 1704 according to the first area identifier;and forward the handover request message to the relay node 1701, so thatthe relay node 1701 performs, according to the handover request messagea control operation of accessing the relay node 1701 on the UE. The basestation 1703 is configured to receive a measurement report sent by theUE, where the measurement report carries the first area identifierobtained by the UE from the system information broadcast message that isreceived from the relay node 1701; according to the first areaidentifier, send a handover required message to the mobility managemententity 1704, so that the mobility management entity 1704 sends,according to the first area identifier, a handover request message tothe control base station 1702 that controls the relay node 1701, wherethe handover request message indicates that the UE requests to be handedover from the base station 1703 to the relay node 1701.

Functions of each module in this system embodiment are the same as thespecific description in the embodiments shown in FIG. 14-FIG. 17, anddetails are not described here again.

Through the handover system in a relay network according to theembodiment of the present invention, a first area identifier thatidentifies the RN is allocated to the RN, so that the UE can be normallyhanded over from the eNB to the RN in the relay network.

Persons of ordinary skill in the art may understand that all or a partof the steps of the method according to the embodiments of the presentinvention may be implemented by a program instructing relevant hardware.The program may be stored in a computer readable storage medium. Whenthe program is run, the steps of the method according to the embodimentsof the present invention are performed. The above storage medium may beany medium that is capable of storing program codes, such as an ROM, anRAM, a magnetic disk, and an optical disk.

Finally, it should be noted that, the above embodiments are merelyprovided for describing the technical solutions of the presentinvention, but not intended to limit the present invention. It should beunderstood by persons of ordinary skill in the art that, although thepresent invention has been described in detail with reference to theforegoing embodiments, modifications can be made to the technicalsolutions described in the foregoing embodiments, or equivalentreplacements can be made to some technical features in the technicalsolutions, as long as such modifications or replacements do not causethe essence of corresponding technical solutions to depart from thespirit and scope of the present invention.

What is claimed is:
 1. A handover method in a relay network, comprising:sending, by a control base station, a response message to a relay nodeaccording to a received interface setup request message, wherein theresponse message carries a first area identifier allocated to the relaynode when an interface is setup to connect the relay node; and receivinga handover request message sent by a mobility management entity, andforwarding the handover request message to the relay node by identifyingthe relay node from the first area identifier obtained from the responsemessage, so that the relay node performs, according to the handoverrequest message, a control operation enabling access to the relay nodefrom a terminal, and wherein the first area identifier enables themobility management entity to send the handover request message to thecontrol base station.
 2. The handover method in the relay networkaccording to claim 1, wherein the allocated first area identifier is afirst evolved universal terrestrial radio access network cell globalidentifier ECGI carried in the response message, and the first ECGIcomprises an identifier of the control base station.
 3. The handovermethod in the relay network according to claim 1, wherein the allocatedfirst area identifier is a first tracking area identity carried in theresponse message, and the first tracking area identity is correspondingto an identifier of the control base station.
 4. The handover method inthe relay network according to claim 3, further comprising: sending abase station configuration update message to the mobility managemententity, wherein the base station configuration update message carriesthe first tracking area identity.
 5. The handover method in the relaynetwork according to claim 1, wherein a portion of the first areaidentifier represent an identifier of the control base station, and thehand over request message is sent in accordance with the identifier ofthe control base station.
 6. A control base station, comprising: atransceiver configured to: send a response message to a relay nodeaccording to a received interface setup request message, wherein theresponse message carries a first area identifier allocated to the relaynode; and receive a handover request message sent by a mobilitymanagement entity, the handover request message carrying the first areaidentifier and the first area identifier enabling the mobilitymanagement entity to send the handover request message to the controlbase station, and a processor coupled to the transceiver, configured toidentify the relay node from the first area identifier obtained from theresponse message, and wherein the transceiver is configured to forwardthe handover request message to the relay node identified by theprocessor.
 7. The control base station according to claim 6, wherein,the transceiver is configured to send a base station configurationupdate message to the mobility management entity; the base stationconfiguration update message carries the first area identifier; thefirst area identifier is a first tracking area identity carried in theresponse message; and the first tracking area identity is correspondingto an identifier of the control base station uniquely.
 8. A handovermethod in a relay network, comprising: allocating, by a control basestation, a first area identifier to a relay node when an interface issetup to connect the relay node; forwarding a handover request messageto the relay node by identifying the relay node using the first areaidentifier, the relay node performing a control operation enablingaccess to the relay node from a terminal according to the handoverrequest message, and wherein the handover request message is sent to thecontrol base station that is identified by a mobility management entityusing the first area identifier.
 9. The handover method in the relaynetwork according to claim 8, wherein system information broadcastmessage carrying the first area identifier is sent to terminals in acoverage area.